This application seeks to elucidate the relationship between particle material and physical characteristics and their plasma-acquired protein corona in prescribing their margination (localization and adhesion) to the vascular wall from bulk blood flow relevant in many cardiovascular diseases (CVDs). In general, vascular wall- targeted carriers offer great opportunities to improve the treatment of CVDs through their imaging and drug delivery capabilities that potentially provide safer, more efficient and effective interventio associated with enhancement of imaging and/or localization of drug release. Several vascular endothelium-regulated processes, e.g. chronic inflammation and angiogenesis, are involved in the pathology of atherosclerosis, as with most cardiovascular diseases; therefore, targeting therapeutics via disease-induced endothelial cell (EC) markers could provide a viable, non-surgical approach to imaging and delivery of therapeutics aimed at disease prevention or reversing established disease. Effective vascular-targeted carriers must successfully navigate the blood stream to reach the target, including being able to avoid immune clearance, find the vascular wall from the cell dense blood flow, and overcome disruptive forces to bind at the target site. In addition to identifying appropriate target epitope(s), identifying carrier propertis - including size, shape, and surface characteristics - that allow for optimum carrier localization and interaction with the vascular wall is crucial to this goal. Here, we hypothesize that the carrir material characteristics and its ensuing protein corona impact the capacity for a carrier system to localize and adhere to the vessel wall from bulk blood flow in addition to modulating immune clearance. This hypothesis is based on (1) our preliminary observation that poly(lactide-co-glycolic) (PLGA) microspheres show significantly lower adhesion to activated EC monolayers from human blood flow relative to polystyrene spheres of the same size, ligand coating and surface charge; though PLGA is slightly denser than blood while polystyrene is density-neutral in blood; and (2) recent literature that show nanoparticles of different polymeric materials coated with the same high PEG density absorbed different levels and types of proteins on their surfaces. The specific aims of the proposed work are: to evaluate (1) the role of carrier material characteristics and their ensuing plasma-acquired protein corona in the differential margination of spherical carriers from human blood flow; (2) the coupled effect of material type and material hydrophobicity, surface coating, and particle size and shape in prescribing carrier margination; and (3) the role of cell-carrier interaction and electrostatic repulsion/attraction at the vascular wall in the distinct margination of carriers associated with their protein corona. To our knowledge, the proposed work would be the first attempt to explore the role of opsonization in the differential margination of different biodegradable polymeric carriers in bulk human blood flow relevant in several CVDs, particularly for imaging and therapeutic intervention in atherosclerosis. The overall success of our proposed work would provide a solid scientific framework for the engineering of sophisticated vascular-targeted systems that would have implications beyond treating cardiovascular diseases.